ANOSOGNOSIA
Anosognosia—sometimes called “lack of insight”—is a medical condition that affects how the brain works. It prevents a person from understanding or accepting that they have a mental illness or brain disorder. This isn’t the same as denial. People with anosognosia aren’t simply refusing to admit something hard—they truly cannot recognize that something is wrong. Their brain is unable to process that information.
How Common Is It?
Anosognosia is very common in certain mental and neurological conditions. Research shows it affects:
50% to 98% of people with schizophrenia
Around 40% of people with bipolar disorder
Over 80% of people with Alzheimer’s disease
10% to 18% of people who have paralysis on one side after a stroke
The brain keeps an ongoing image of the body and its condition. When something changes—like an illness or injury—the brain usually updates that image so you know something is wrong. But in anosognosia, the part of the brain that updates this “self-image” is damaged. Because of this, the person doesn’t realize there’s a problem at all.
This makes anosognosia very different from someone who is in denial. Denial is when a person avoids accepting the truth because it’s painful or scary. In anosognosia, the brain can’t recognize the problem in the first place. The person isn’t choosing to ignore it—they truly can’t see it.
Because they don’t know they are ill, people with anosognosia often don’t believe they need treatment. Some may even refuse help completely. This can make it much harder for them to get better or stay safe, and it can be very challenging for families, doctors, and caregivers to support them.